Inoculation of a suspension of killed or attenuated pathogenic micro-organisms to stimulate the formation of antibodies is known as
The correct option is A Vaccination
A vaccine contains an agent that resembles a disease-causing microorganism and is often made from weakened or killed forms of the microbes, its toxins or one of its surface proteins.
The agent stimulates the body's immune system to recognize the agent as a threat, destroy it and keep a record of it so that the immune system can more easily recognize and destroy any of these microbes that it later encounters.
So the correct answer is the option 'Vaccination'.